Tightwire sports equipment

ABSTRACT

A cable forming a tightwire is supported above the ground at low height by a pair of spaced apart standards with the ends of the cable secured to ground anchors and stretched over the standards by turnbuckles. A tension spring is connected in the cable string to limit tension forces. The standards have platforms at about cable height and the cables are secured to the standards by Ubolts. A pair of tubes at the sides of the standard have upper ends extending substantially above the platforms to be grasped by user hands in stepping onto the tightwire and leaving the tightwire, and the lower ends of the tubes penetrate the ground, the standards having pad means bearing on the ground to limit ground penetration.

United States Patent [1 1 Bowen [451 Aug. 28, 1973 TIGHTWIRE SPORTS EQUIPMENT [76] Inventor: Duane C. Bowen, 2551State St.,

Carlsbad, Calif. 92008 22 Filed: Jan. 21, 1971 21 App1.No.: 108,606

Related US. Application Data [52] US. Cl. 272/60 [51] Int. Cl. A63b 23/04, A63j 7/00 [58] Field of Search 272/21, 22, 23, 24,

272/57 R, 60, 62; 24/73; 287/75-82; 273/29 R, 29 BB, 29 BC, 29 BD [56] References Cited UNITED STATES PATENTS 1,419,191 6/1922 Acker 272/21 2,508,925 5/1950 Metz 272/23 X Dunscombe 273/29 B FOREIGN PATENTS OR APPLICATIONS 525,395 8/1940 Great Britain 273/29 BB 185,567 9/1922 Great Britain.... 273/29 BD 16,342 10/1929 Australia 273/29 BB 1,038,836 8/1966 Great Britain 2 73/29 BB Primary Examiner-Anton O. Oechsle Assistant Examiner-Richard .1. Apley [57] ABSTRACT A cable forming a tightwire is supported above the ground at low height by a pair of spaced apart standards with the ends of the cable secured to ground anchors and stretched over the standards by tumbuckles. A tension spring is connected in the cable string to limit tension forces. The standards have platforms at about cable height and the cables are secured to the standards by U-bolts. A pair of tubes at the sides of the standard have upper ends extending substantially above the platforms to be grasped by user hands in stepping onto the tightwire and leaving the tightwire, and the lower ends of the tubes penetrate the ground, the standards having pad means bearing on the ground to limit ground penetration.

18 Claims, 10 Drawing Figures Patented Aug. 28, 1973 3,754,757

L5 Sheets-Shoot I NVE NTOR.

Patented Aug. 28, 1973 3,754,757

3 Sheets-Sheet 3 INVENTOR.

TIGHTWIRE SPORTS EQUIPMENT CROSS-REFERENCES a. This is a continuation-in-part of the copending U.S. Pat. application Ser. No. 749,336, filed Aug. l, 1968, now abandoned.

b. Other copending patent applications by the same inventor and under the same title are Ser. No. 839,179, filed July 7, 1969, now US. Pat. No. 3,570,847, and Ser. No. 861,544, filed Sept. 16, 1969, now U.S. Pat. No. 3,570,848.

BRIEF SUMMARY OF THE INVENTION My invention concerns an improvement in tightwires adapting the same for amateur use, for low heights, and for an economical construction readily assembled for residential backyard or park usage, which is achieved essentially by a single cable tensed by turnbuckles between ground anchors and extending over a pair of low standards which have lower portions penetration the ground and which have platforms and have uprights to be grasped by hand extending above the platforms.

Tightwire walking has been considered a skill for professional circus performers and the like, whereas I have found it to be a skill that can be acquired by amateurs and is no more difficult than many other amateur sports. Tightwire walking has been considered a dangerous act, whereas I have found it to be relatively safe and to be less dangerous than many other amateur sports when the idea is discarded that a tightwire must be high and when it is realized that the wire can be, for example, a foot and a half off the ground. It is an objective of my invention to provide a tightwire suitable for amateurs, particulary a tightwire a relatively short distance off the ground. j

I have found it more feasible to consider a tightwire as a piece of play equipment if it is an outdoor sport. This is because of several reasons: First, forces in tension are relatively high and it is usually more feasible to provide adequate anchoring in the ground than to anchor in the floor of a building, i.e., holes in the ground are of little concern and ground anchors are relatively easy to secure and are inexpensive. Although the following description is primarily in terms of the ground and it will be understood that this is, generically, a supporting surface, and concrete or even a wooden fioor could be substituted. Second, space in excess of twenty feet is desirable for a tightwire and this may be difficult to provide, at least for this purpose, in a building. Even head room in a building can be a problem, i.e., a person on an 18 inch tightwire and, perhaps, using an umbrella in balancing can require more height than the usual 8 foot ceiling. Third, a grassy lawn is a suitable surface whereas a pad might be desirable on a hard floor. The above reasons particularly apply to family use, and would not apply as much to a school or the like that has a gymnasium wherein securing to a floor may not be objectionable, space may be available, ceilings are high, and floor mattresses are common items of equipment. Of course particularly for family use, the equipment must sell for a low price relative to what a school may pay for an item of gymnasium equipment. Further objects of my invention are to provide equipment particularly suited'for outdoor use and to provide apparatus suitable for family recreational use in price and in other respects, although I do not mean to exclude adaptation to indoor use or to the market to schools and the like.

The inherent appeal ofa tightwire is evidenced by the frequent play of young people in balancing and walking on other elevated, narrow surfaces such as the top rail of a wood fence, a brick or cement retaining wall, a fallen log, a train rail, a plank, etc.

For purposes of facility in use and for safety purposes, standards should have integral platforms and preferably means to be grasped at hand height in stepping off the platform onto the tightwire or returning to the same. It is an object of my invention to provide such platforms and such means to be grasped.

The above discussion is based on experimentation and on the construction and experimental use of two quite different prototypes.

Further objectives and advantages of my invention will be best understood from the following description, read with reference to the drawings, in which:

FIG. 1 is a perspective view of a specific embodiment of my tightwire means, a user being shown balancing on the wire and using a long pole to assist him in balanc- FIG. 2 is an enlarged view taken generally on line 2-2 of FIG. 1, with the ground shown in section to reveal the ground penetration of the standard, the ground anchor being shown in dotted lines in the background.

FIG. 3 is a partial view taken on line 3-3 of FIG. 2.

FIG. 4 is a partial perspective view of a standard modified to provide adjustable wire height, the alternative ground bearing pad positions being indicated in dotted lines.

FIG. 5 is a partial exploded perspective view of parts of a second modified standard showing a second method of providing adjustable wire height.

FIG. 6 is an enlarged sectional view of ground penetration means taken on line 66 of FIG. 5.

FIG. 7 is an enlarged, partial side view showing the parts at an end of the cable and showing a modification in the form of a secondary, safety cable.

FIG. 8 is a partial, enlarged view, partly in section, of the portion of a standard supporting the cable and forming a platform.

FIG. 9 is a partial top view of a standard and a cable supported thereby.

FIG. 10 is a partial, enlarged perspective view of a modified form of standard ground penetration means.

In the past the expressions high wire, tightwire, and tightrope have been used somewhat interchangeably, although it appears that the expression tightrope probably derived from the time when good wires or cables were not available, that the expression tightwire may have derived from a time when wires but not suitable cables were available, and that the expression highwire probably was derived similarly to the expression tightwire,'although there is a difl'erence between a high wire perhaps 50 feet in the air and a low wire which professional performers sometimes use which may be 8 or 10 feet high. When good quality cables became available it appears most performers used cables although the expression tightwire rather than tight cable is used and although the former expression suggests single stranded rather than multiple stranded wire. The point to mentioning this word usage is that when I use the expression cable or tightwire 10 in the specification and claims, I merely do so for convenience and do not mean to exclude any suitable rope,

wire or cable, although at this time multiple stranded metal cable is the most applicable medium not only for this invention but also for professional usage. It will be understood that particularly for outdoor usage, but also preferably for indoor usage, a corrosion resistant cable should be used such as stainless steel.

A good grade of cable 10 will withstand at least a couple of thousand pounds even in one-quarter inch diameter, but I prefer to use at least one-quarter inch cable, and preferably five-sixteenth inch cable, partly for foot comfort. The so-called tennis shoes or sneakers are suitable for amateur use of the tightwire and the wire will be comfortable through the rubber soles. About the only safety precaution to a user of my tightwire is to use such a shoe, as distinguished from even a rubber soled street shoe, because a dry tennis shoe should not slip from the wire, whereas a street shoe may slip and cause an uncomfortable fall even for a youth. To go off a wire because of unbalance is not usually troublesome because the feet and body are in position to catch the user on the ground,.whereas a foot slip may give the body a tipping moment.

One primary discovery l have made is that acceptability of a tightwire for amateurs depends on low heights. Different heights were experimented with, but I have found about 18 inches to about optimum at least for beginners. At this height, the ground can be cleared about 1 1 inches at the center of the tightwire even with some dynamic force in addition to he static force of the weight of a user and even when tightwire l bears the weight of an adult user. Distances looking down are appreciably different than distances looking up or in elevation, and I have found that 18 inches give sufficient sensation of height to a user on the wire. It will be observed, however, that 18 inches is a relatively short distance even for a child, so that acceleration is nominal in any falling, and so that the cable will be accommodated between the legs of even a child of any size if he lands with his feet on opposite sides of the cable, and so that in going off the wire to the side, the distance is only a moderate step. Aside from the matter of safety, there are important psychological aspects of a short height. The first, already alluded to, is that 18 inches appears surprisingly high to a user. The second psychological factor is compensation for the immediate reactions of height and danger when the word tightwire is used. Without this latter factor, 24 inches would not be unreasonable from safety considerations as children commonly play with inherently more dangerous equipment, such as a slide, a swing, a bicycle, or even a tree to climb.

For purposes of the claims, it is needed to define these low heights for purposes of definitiveness and yet to allow some latitude as to a few inches change. One definition based on an experimental prototype is above the supporting surface (or ground) no more than about l8 inches which is defined as a maximum of 20 inches. A second, broader definition based on an experimental prototype is above the supporting surface no more than about 24 inches which is defined as a maximum of 27 inches. It is realized that use of this equipment will result in some youths pursuing the sport to full amateur (or even semiprofessional) skill and that part of the sport will be higher wires within certain safety limits. FIGS. 4 and recognize this desire for more height with increased proficiency by providing adjustable height models. For this high skill usage, a

third definition is made which is above the supporting surface no more than about 48 inches which is defined as a maximum of 52 inches, which is a height below that used by professional low wire walkers but is a height which is consistent with reasonable safety and considerable height sensation for the proficient user. No broader definitions of heights are used than the above because any usage of my equipment higher than this third definition distinguishes professional equipment by the structure used from the present invention rather than from the height, and greater heights require skills comparable to those of professionals.

One additional advantage of the I8 inch or even the 24 inch heights is that the user platforms 14 provided do not require steps to get up to the same, which reduces complexity and cost of the equipment.

Cable 10 is preferably a single integral member from the tigthening ans securing assembly at one end to the other, as distinguished from a structure in which the cable is broken at each standard 16 and platform 14 so that one length is the tightwire between and secured to standards 16 and platforms l4 and two other cables are provided in the nature of guy-wires, each secured to the ground at one end and to the standard 16 and platform 14 at the other end. The economy of, instead, having a single cable, will be evident. A second benefit of having a single cable length is that only two cable securing loops are needed instead of four, thereby reducing possibilities of breakage or insufficient fastener torquing and thereby increasing the integrity of the tightwire. Of course it is undesirable to have any failure when a user is on the tightwire, even when the wire is at low heights. The purpose of a single length of cable was accomplished, as will hereafter appear, by running the cable through a U-bolt 12 at each standard 16 and securing the cable with the same. A third advantage of the use of the single cable is that the platform 14 can be smaller and be built differently, i.e., if a separate tightwire were looped and secured with cable clamps at each platform 14, then platform 14 would have to be cantilevered out beyond the loop as it will be understood that the user does not want to start out on a tightwire by stepping on a loop and on cable clamps. Other than the matter of expense and complexity of such cantilever to platform 14 is the unobvious factor that a platform extending much beyond standard 16 could be hit by a falling user, whereas ,without this cantilever I have provided vertical, pole-like uprights 18 to be grasped by the hand which tend to avoid such platform corner protruding much from the general plane of the standards. It will be observed that the general construction of standards 16 is to define generally an upright plane by the structure facing the other standard (the walking area) from the top of upright 18 to substantially the ground level, so that a user slipping or otherwise falling toward the standard will have a maximum chance of catching himself and a minimum chance of striking a corner or the like with his head or other part of his body. It is to the same end that platform 14 is given a sponge rubber covering pad 20 which is split, divided and or spaced at the location of cable 10 as shown particularly in FIGS. 8 and 9 to leave room for the cable.

I designed a number of standards and constructed a much different prototype before arriving at a prototype shown particularly in FIGS. 1-3 of the drawings which operated most satisfactorily in all respects. The basic standard construction includes two tubes 22 which at their upper ends become two uprights 18 which extend about 40 inches above platform 14 to a convenient height to be grasped by the user in getting up on platform 14, leaving onto tightwire 10, or returning from tightwire 10. Medially, tubes 14 are part of the basic load bearing frame which includes platform 14, and at their lower ends tubes 22 become ground penetrating,

means 24. Tubes 22 are spaced about 20 inches which will accommodate an adult between uprights 18 but the uprights are not spaced too far apart for ready grasping by children. Even in apparatus designed for young children, spacing of tubes 22 approximately 12 inches apart would be a minimum to accommodate a 'child therebetween and a height of tubes 18 of approximately 30 inches above tightwire would be a minimum to be at a convenient height to grasp in getting on and off tightwire 10.

Platform 14 is built up from an angle iron 30 welded to tubes 22 and a flat piece of metal 32 fonned into a channel with flanges 34, the channel 30 being secured to angle iron 30 and preferably also welded to tubes 22. Two holes (not shown) through channel 32 and angle iron 30 accommodate U-bolt 12 which is used to secure cable 10 at the location of each standard. Nuts 36 for U-bolt 12 are on the lower side. Channel 32 is relieved at its edges by slanted grooves 33, 35 ,or by radiusing to avoid abrupt bending of cable 10 over tight angular edges. Braces 38 are welded to tubes 22 and angle iron 30. These braces help keep standard 16 from racking and help bear the load of the normal tensing of cable 10 and of the weight of a user thereon.

A ground bearing pad 40 on each standard 16 helps form the basic strength of the standard but has a primary function of bearing on the ground to limit ground penetration by tube portion 24. Pad 40 is formed from plate metal and is welded to tubes 22. The plate being fairly broad, i.e., 6 inches, it has a secondary function of acting against'upsetting of the standard, which is particularly convenient in installation of the equipment when the cable l0-is tensed and before U-bolts 12 are secured. Note that the pad 40 and the ground penetrating means 24 being spaced to each side of the upright plane of the cable (this should be a minimum of 6 inches to each side of that plane), this structure prevents sidewise tipping of standards (transversely of cable 10), although it will be observed that there are no substantial forces tending to tip the standards sidewise during use, i.e., theuser produces little lateral force and his weight and the basic tensing of the cable do not tend to upset the standards sidewise as long as they have good bearings lateral of said upright plane. Although the ground bearing pad does not need to .have the full dimensions of plate 40 to have a substantial effect in limiting ground penetration by tube portions 24, the horizontal area of extension or projection of pad 40 out from standard tube portions 24 should be at least a couple times the horizontal area cross-section of the avoided by the use of metal ground anchors 50. By my structure, all structure needed for an installation can be simply boxed, installation can be accomplished in a short time (the only time consuming chore being that of augering ground anchors 50 in place which can be more or less difficult depending on the nature of the ground), and all that is needed in the way of tools are wrenches, and something like a bar or pipe for leverage in augering anchors 50 into the ground, plus the hammer end of an axe or a seldge to drive ground penetration means 24.

When the forces are properly analyzed, it will be realized' that the requirements of ground penetration of tubular portions 24 is rather nominal as there are little in the way of forces that tend to dislodge them. These are not in the nature of posts that act primarily against bending. The ground penetration means 24 instead merely hold the lower ends of standards primarily against slipping endwise of the cable and secondarily against slipping sidewise of the cable. The forces produced by the cable basic tension and by the users weight mostly only tend to force penetration means 24 farther into the gorund which is the purpose of pad 40 in limiting that penetration). When a user is on the wire, the balancing of forces, will be evident as cable 10 bends downwardly on the side of the standard toward the other standard because of the users weight and the cable extends downwardly on the outside of the standard to ground anchor 50. The purpose of clamping cable 10 by U-bolt 12 at each standard is to further relieve penetration means 24 from a post-like function. It is convenient to have some post-like characteristics as there is some tipping of standards 16 in the upright plane of cable 10 during use and this is especially convenient during initial installation when the cable is given some tension but before securing it to standards 16 by U-bolts 12, but these functions are purely secondary. This means that the. ground penetration means 24 could be less extensive, differently located, or differently configured, but they work very well in the present configuration. Ground penetration means 24 (the portion of the standard tubular uprights penetrating the ground) should extend into the ground at least several inches as the function of limiting shifting of the lower ends of the-tubes reasonably requires a couple inches ground penetration, although it will be understood that greaterlength will be common. Likewise, ground bearing pad 40 could be limited to areas adjacent each ground penetrating member 24, etc., but the present configuration is preferred because pad 40 has secondary purposes including forming part of the boxlike structuralframe of standard 16. Note should be taken of the fact that ground penetrating members 24 to an extent work" in the ground, which means that standards 16 can pivot somewhat about their lower portions in the vertical plane of cable 10. After cable 10 is secured to standards 16 by U-bolts 12, it is this small pivoting movement of standards 16 that permits some separation or reverse movement thereof as cable 10 is further tensed by turnbuckles 54 and by user weights, i'.e., there would be different structural, strength and system probems if standards 16 acted like truly rigid posts. The limited but substantial pivotal adjustability of each standard as a whole about the lower end thereof, in the vertical plane of cable means 10, is at least several degrees.

There are other applicable tightening means for cable 10 other than turnbuckles 54, including even block and tackle means, but I have found the turnbuckles to be adequate, safe and economical. A five/eighth inch turnbuckle is applicable. Preferably a turnbuckle is provided at each end to give sufficient tightening capacity as there will be a tendency for parts such as ground anchors 50 to work further into the ground, and, also, keeping standards 16 substantially vertical during tightening is better accomplished by having a turnbuckle on each end. All of the parts in the cable string are designed for a minimum of 2,000 lbs. and a one-half inch to five-eighths inch ground anchor (with about inch auger blades 56 and about 4 feet long), the one-fourth or five-sixteenths inch cable (and the associated cable clamps), and the five-eighths inch turnbuckle all exceed this strength, some by a good deal such as the cable that may have 5 6,000 lbs. breaking strength. Turn-buckles 54 have a hook 60 on one end and an eye 62 on the other end. Hooks 60 are engaged with the eyes 64 of ground anchors 50 and eyes 62 of the turnbuckle connect directly to cable or via spring 70.

Ground anchors 50 may be of a type on the market formed by a rod having an eye 64 at the upper end and having welded thereto near the lower end a helical auger blade 56 which extends annularly about the rod approximately one' 360 turn. Anchors 50 are screwed or augered into the ground either vertically or in the direction of the connecting portion of cable 10. If augered vertically, in the process of installation and operation the rod will be pulled in the ground to a position more in alignment with the connecting portion of cable 10. A bar through eye 64 can be used for mechanical advantage in this augering operation. Another design of helical means on the market, to screw the rod-like ground anchors 50 into the ground, is to form at least the lower portion of the rod as a helix, so that the rod itself is helically shaped rather than requiring securing of a helical blade on the rod.

Spring 70 may be used to control maximum tension in cable 10 and associated parts. For this purpose the spring only needs to be used at one end of the cable string. The usage thus depends partly on the safety factors used in the design, i.e., it will be more applicable if the safety factors are low. A spring model used, as a specific example, has one-half inch round wire diameter, 2 '1; inch mean coil diameter, active coils, and a modulus in tension of 11,500,000, and in formed of high quality carbon steel wire. The use of a spring induces some extra give to the tightwire which may be favored by some users, but it is believed more users prefer as tight a wire as possible, which means that the spring should have as little deflection as feasible consistent with safety factors. Spring 70 is a simple coil spring ending at each end with a return'bend or hook, one end of which engages in eye 62 of turnbuckle 54 and the other end of which is engaged in a cable loop. In FIG. 3, spring 70 is shown as covered with a shroud 85 to prevent children getting fingers therein when it is expanded, i.e., a heavy canvas tube tied in place.

For a more detailed example of the forces involved in the cable string and of the function of spring 70, consider the example or one prototype of my invention (using the spring described above) in which the standards were separated 15 feet and the deflection of cable 10 was 7 inches at the center when loaded with an adult user at that point. Applying vector analysis and an assumed 200 pounds force in the center, this may be calculated to result in about 1,200 lbs. tension in the cable string. For the small angles of deflection involved, a general approximation is that the tension in.

the cable, with a person on it, is inversely proportional to the vertical deflection at the center (the analysis being based on the fundamental condition of center loading). To limit the tension in the cable below a safe working limit, the turnbuckles 54 should not be tightened beyond that point at which the weight of a 200 lbs. person causes less than a given safe deflection. With the design details given above, tightening of turnbuckles 54 until the coils in spring separate readily perceptibly (without a user on cable 10) will be within such safe working limits. The use of coil tension spring 70 in the cable string or system, reduces the system spring rate and thus provides the desired deflection with less close attention to the correct adjustments of turnbuckles 54. Without spring 70, the tension would need to be defined to an assembler in terms of a torque measuring wrench, in terms of a given length of mechanical advantage of a wrench or bar and moderate manual force, or in other terms or equipment avoiding over-torquing. For a close-to-margin (low safety factor) design, it may be more economical to employ lighter cables, anchors, etc., and to compensate with the spring 70 to permit the needed deflection under load, than to employ heavier and stronger elements in the cable system.

Cable 10 is secured to tension spring 70 at one end and to an eye 62 of one of turnbuckles 54 at the other end by the formation of a cable return loop at each end. Each loop is secured by a pair of cable clamps 82.

An above indicated, concern about possible breakage in the string of cable and associated parts depends on safety factors used and any susceptibility of parts to corrosion. FIG. 7 shows a modification of a fail-safe type in which a by-pass or secondary cable is secured to cable 10 at one end by cable clamp 92 at a point inward of other parts in the cable string. The other end of cable 90 is secured by a loop 94 and a cable clamp 96 to eye 64 of anchor 50 or to the eye of a separate smaller anchor if there is concern about the strength of the ground anchor or its corrosion. For con- .venience and clarity of illustration, to separate it from other parts, by-pass cable 90 is shown as looser than it actually would be in practice.

Mention previously has been made of height adjustability. FIGS. 4 and 5 show two modified forms of the invention to accommodate height adjustment. In FIG. 4, the three positions 100, 102, 104 of ground bearing pad 40 should be taken as positioning platform 14 distances of 18 inches, 24 inches and 48 inches respectively. Of course ground penetrating means 24 has more or less ground penetration depending on the position of ground bearing pad 40. Adjustment of position of pad 40 is accomplished by having three pairs of openings 110, 112, 114 in each tube 22, by providing a pair of upper and lower angle members 116 on each end of pad 40, and by securing pad 40 in adjusted position by a pair of bolts 118 selectively positioned in openings 110, 112, 114 and extending through matching openings in angle members 116. Bulk in shipping most articles of manufacture is a consideration and it will be observed that the removable connection of pad 40 will lead to disassembly of standard 16 for shipment if braces 38 and platform 14 are likewise bolted instead of welded to tubes 22. Bolting of platform 14 would permit height adjustability by changing location of the platform rather than the pad.

FIG. illustrates another method of providing height adjustment in which inner and outer tubular parts are used for height adjustability and secondarily for disassembly into compact form for distribution, sales, shipping and storage. Tubular body 22 is formed by an upper section 120 (to form uprights 18 for hand gripping), a second section 122 to form the basic truss with brace 18 and angle iron 30, an optional section 124 for height adjustment, and a lower section 126 forming, essentially, ground penetration means 24 (and having pad 40 welded thereto). Without section 124, the platform height should be taken as 18 inches from the ground and with section 124 the platform height should be taken as 24 inches from the ground. If more than one section 124 is provided, or if a longerand a shorter section 124 are provided, further adjustability in platform height is accommodated. Each'section has an upstanding'or depending tube 125 of smaller size (secured therein by welding) to fit inside the next tubular section, except section 126 may merely be of smaller tubular size. If the inner and outer tubes are a close fit, set screws are not needed because the primary forces on the standard assembly during use tend to force them closer together rather than to separate the same. The only reason to have a separable upper section 120 is for disassembly for shipping as it has no function in adjusting platform height, an d the separable upper section 120 could be used with non-adjustable standards just for the purpose of minimizing necessary package length for packaging, storing and shipping.

The equipment can be readily assembled. As a first step, anchors 50 are properly located by laying out cable and making allowance for adjusted distance due to the fact that the cable rises to the standards. An extra amount, such as a couple of feet is allowed in cable length versus anchor spacing to allow for cable loops, some allowance for error, etc. The cable length is reduced for the distances represented by turnbuckle 54 (in expanded condition) and spring 70, which can be accomplished by laying these parts out or by measuring and calculating. Little is lost by providing extra cable length, whereas the installer would notwant to be short as anchor installation involves the most work.

After anchors are installed, standards 16 are located relative to the vertical plane which the cable will occupy, so that cable clamps 12 will be properly located. Generous tolerances can be used in this location as some misalignment from the ideal is not critical. The standards 16 are located appropriate distances from anchors 50. This distance is not critical but 42 to 48 inches is suitable. Ground penetration means 24 being pointed, standards 16 can be set in the ground readily, i.e., the installers weight on platform 14 will gain considerable penetration is soft ground and the ground penetration can be completed by the use of a sledge or the hammer end of a single bitted axe until ground bearing pad 40' rests firmly on the ground (or grass sod).

Next the cable string is assembled but cable clamps 82 are not fully tightened at one end until the cable is tensed by a good pull. U-bolts 12 are not tightened until cable 19 is tightened generally horizontally. However this is not a critical item as any differences between cable length (tensed) between U-bolts 12 and the distance between U-bolts is accommodated by slight tipping of standards 16 once turnbuckles 54 are tightened, as related before. When cable 10 has been given general tightening by pulling and cable clamps 82 and U- bolts 12 are torqued, then turnbuckles 54 are tightened until the tightwire has desired tension. During first use, the turnbuckles will need to be tigthened a number of times until anchors 50 reach final alignment in the ground.

A modified method of installation can be based on the observation that, after erection, the distance between the standard U-bolts is substantially the same as the' distance between the lower ends of the standards. The U-bolts on the standards could be first tightened on the cable and then the standards could be made to penetrate the ground on the same spacing. Then when the ends of the cable are connected to the ground anchors and the cable string is tensed, bringing one standard to a vertical position will necessarily bring the other standard to a vertical position.

The structure and operation of my invention, advantages thereof, and how objectives are met will appear from the foregoing description and from the drawings. It should be understood that 1 have described and shown specific embodiments for purposes of illustration and not by way of limitation. Those skilled in the the art upon learning of my invention may be inspired to design modifications of myequipment to provide tightwire walking means particularly in the amateur market. I want to cover those modifications made because of learning of my invention and properly lying within the scope of my invention.

1 claim:

1. Sports equipment in which tigthwire means is supported above the ground, comprising:

a. a pair of spaced apart ground anchors secured in said ground b. a pair of spaced apart standards between said anchors supported by said ground and having supporting means above said ground c. cable means connected between said anchors and extending from said anchors to said supporting means of said standards, and tightening means connected to said cable means and tightening the same, said cable means being stretched and extending from one anchor to the supporting means of the adjacent standard and then to the supporting means of the other standard and then to the other anchor and providing tightwire walking means between said standards,

d. a vertical, pole-like upright member at each sideof each standard and said upright members penetrating the ground at least a couple of inches for stability of said standards and being spaced transversely of said cable means to each side of said cable means thereby acting to prevent sidewise tipping of said standards.

2. The subject matter of claim 1 in which each standard has a platform at about the height of said cable means extending between said upright members of each standard thereby providing supports for users starting on said tightwire walking means and in leaving an end of said tightwire walking means.

3. The subject matter of claim 2 in which each upright member extends above said cable means at least to the level of the hands of users walking on said tightwire walking means whereby uses leaving said platform of a standard or coming to said platform will have an upright at hand level to grasp for support, said upright members being spaced apart a sufficient distance to accommodate a user on said platform between said upright members.

4. The subject matter of claim 1 in which each standard has pad means limiting penetration of the ground by said upright members and said pad means is a flat, horizontally disposed plate resting on the ground and extending between the lower portions of said upright members, said upright members having pointed lower ends below said plate for ease of ground penetration, said platform including a flat, horizontally disposed, plate-like member, said supporting means being a portion of said plate-like member, the corners of said plate-like member being relieved in the area of said cable means thereby preventing bending of said cable means over square corners, brace means between said upright members and said plate-like member in the area of cable means support for strength in supporting said cable means and for bracing the standard against racking movement, said upright members being spaced to each side of said cable means at the ends of said plate and plate-like member providing room' between said upright members for a user on said platform.

5. Sports equipment in which tightwire means is supported above the ground, comprising:

a. a pair of spaced apart rod-like ground anchors secured in said ground by screwing into said ground, said anchors including helical means having a screw action in the ground b. a pair of spaced apart standards between said anchors supported by said ground and having supporting means above said ground cable means connected between said anchors and extending from said anchors to said supporting means of said standards, tightening means con nected to said cable means and tightening the same, said cable means being stretched and extending from one anchor to the supporting means of the adjacent standard and then to the supporting means of theother standard and then to the other anchor to provide tightwire walking means between said standards, and means securing said cable means with respect to said standards, said cable means consisting only of a single tightwire cable in the area between said standards positioned above the ground no more than about 48 inches.

6. The subject matter of claim 5 in which said ground anchors have eyes and said tightening means consists of a pair of turnbuckles each having a hook engaged in an eye of one of said ground anchors and having an eye on its other end, a tension coil spring having engaging means at each end including one end engaged in the eye of, one of said turnbuckles, said cable means consisting of a single cable connected to the eye of one of said turnbuckles atone end and at the other end secured to the other end of said spring, said supporting means of each standard including a U-bolt securing said cable thereby holding the standard against tipping longitudinally of said cable.

7. The subject matter of claim 5 in which said cable means is secured to said standards and in which each standard has ground penetrating means extending into the ground at least several inches limiting the lower end of each standard from shifting and permitting some limited but substantial pivotal adjustability of each standard as a whole of at least several degrees in the vertical plane of said cable means about the lower portion of the standard thereby accommodating tightening of said cable means, each standard having ground engaging pad means including portions spaced transversely of said cable means to each side of said cable means thereby acting to prevent sidewise tipping of the standard and bearing on said ground, said pad means extending horizontally out from the adjacent portion of each standard and having in the horizontal extension at least a couple times the horizontal area of said adjacent portion whereby said pad means has a substantial effect in limiting standard ground penetration, each standard having a platform at about the height of said cable means thereby providing supports for users in starting on said tightwire walking means and in leaving an end of said tightwire walking means, each standard having upright means extending above said cable means at least to the level of the handsof users walking on said tightwire walking means whereby users leaving said platform of a standard or coming to said platform will have an upright at hand level to grasp for support.

8. The subject matter of claim 5 in which said cable means, anchors, and tightening means form tensed elements including only a single cable whereby the integrity of the tightwire walking means is not impaired by the securing of more than one cable.

9. The subject matter of claim 5 in which each standard has ground penetrating means extending into the ground at least several inches limiting the lower end from shifting.

10. The subject matter of claim 5 in which each standard has pad means bearing on said ground, said pad means extending horizontally out from the adjacent portion of each standard and having in the horizontal extension at least a couple times the horizontal area of said adjacent portion whereby said pad means has a substantial effect in limiting standard ground penetration.

11. The subject matter of claim 5 in which each standard has a platform at about the height of said cable means thereby providing supports for users in starting on said tightwire walking means and in leaving an end of said tightwire walking means.

12. The subject matter of claim 5 in which each standard has upright means extending above said cable means at least to the level of the hands of users walking on said tightwire walking means whereby users starting to walk .the tightwire from a standard or reaching a standard from the tightwire will have an upright at hand level to grasp for support.

13. The subject matter of claim 5 in which each standard includes an upright and pad means secured to said upright and bearing on the ground, said pad means extending horizontally out from the adjacent portion of each standard and having in the horizontal extension at least several times the horizontal area of said adjacent portion whereby said pad means has a substantial effect in limiting standard ground penetration, and said pad means having means for adjustably securing the same to said upright at various distances from said cable means thereby providing for adjustable height of the tightwire above the ground. r

14. The subject matter of claim in whicheach standard includes a tubular upright and in which each standard includes pad means secured to said upright and bearing on the ground and limiting ground penetration by said upright, said pad means being of a size to increase standard ground bearing area several times, and there being interfitting tubular parts of said tubular upright between said pad means and said cable means whereby the height of the tightwire above the ground can be varied by omission or addition of interfitting tubular parts.

15. The subjectmatter of claim 5 in which each standard has an upright extending from the ground to a height above said cable means at least to the level of the hands of users walking on said tightwire walking means whereby users leaving a standard to walk on the tightwire or returning to the standard from the tightwire will have an upright at hand level to grasp for support, and said upright being formed of interfitting parts permitting detachment of a portion of said upright above said cable means from the remainder of said upright thereby reducing package length in disassembly for shipment.

16. Sports equipment in which tightwire means is supported above a supporting surface, comprising:

a. a pair of spaced apart standards supported by said supporting surface b. cable means extending between said standards, said standards having meanssecuring said cable means thereto and means supporting said standards in upright position including means engaged in said supporting surface whereby said standards are held against the tension of said cable means c. means'operative to tighten said cable means be- .tween said-standards (1. said cable means between said standards consisting only of a single cable to fo'rmtightwire means posi in upright position including means'engaged in said supporting surface whereby said standards are held against the tension of said cable means 0. means operative to tighten said cable means between said standards said cable means between said standards consisting only of a single cable to fonn tightwire means positioned above said supporting surface no more than about 48 inches e. said means supporting said standards in upright position including anchor means secured in said sup-.

porting surface at the opposite end of each standard from the other standard and said cable means extending from each standard and connecting to the associated anchormeans, said cable means including only a single cable thereby avoiding impairing cable means integrity by securing more than one cable.

18. The subject matter of claim 17 in which said means operative to tighten said cable means between said standards is a tightening member interposed bemeans, and there being a secondary, by-pass safetytween said cable means and at least one of said anchor cable secured to the cable meansand extending past said tightening member and connecting to the associatcd anchor means whereby upon failure in the connection of the cable means to the tightening member or of the tightening member to the associated anchor means,

1 the by-pass cable will accept the cable means load. 

1. Sports equipment in which tigthwire means is supported above the ground, comprising: a. a pair of spaced apart ground anchors secured in said ground b. a pair of spaced apart standards between said anchors supported by said ground and having supporting means above said ground c. cable means connected between said anchors and extending from said anchors to said sUpporting means of said standards, and tightening means connected to said cable means and tightening the same, said cable means being stretched and extending from one anchor to the supporting means of the adjacent standard and then to the supporting means of the other standard and then to the other anchor and providing tightwire walking means between said standards, d. a vertical, pole-like upright member at each side of each standard and said upright members penetrating the ground at least a couple of inches for stability of said standards and being spaced transversely of said cable means to each side of said cable means thereby acting to prevent sidewise tipping of said standards.
 2. The subject matter of claim 1 in which each standard has a platform at about the height of said cable means extending between said upright members of each standard thereby providing supports for users starting on said tightwire walking means and in leaving an end of said tightwire walking means.
 3. The subject matter of claim 2 in which each upright member extends above said cable means at least to the level of the hands of users walking on said tightwire walking means whereby uses leaving said platform of a standard or coming to said platform will have an upright at hand level to grasp for support, said upright members being spaced apart a sufficient distance to accommodate a user on said platform between said upright members.
 4. The subject matter of claim 1 in which each standard has pad means limiting penetration of the ground by said upright members and said pad means is a flat, horizontally disposed plate resting on the ground and extending between the lower portions of said upright members, said upright members having pointed lower ends below said plate for ease of ground penetration, said platform including a flat, horizontally disposed, plate-like member, said supporting means being a portion of said plate-like member, the corners of said plate-like member being relieved in the area of said cable means thereby preventing bending of said cable means over square corners, brace means between said upright members and said plate-like member in the area of cable means support for strength in supporting said cable means and for bracing the standard against racking movement, said upright members being spaced to each side of said cable means at the ends of said plate and plate-like member providing room between said upright members for a user on said platform.
 5. Sports equipment in which tightwire means is supported above the ground, comprising: a. a pair of spaced apart rod-like ground anchors secured in said ground by screwing into said ground, said anchors including helical means having a screw action in the ground b. a pair of spaced apart standards between said anchors supported by said ground and having supporting means above said ground c. cable means connected between said anchors and extending from said anchors to said supporting means of said standards, tightening means connected to said cable means and tightening the same, said cable means being stretched and extending from one anchor to the supporting means of the adjacent standard and then to the supporting means of the other standard and then to the other anchor to provide tightwire walking means between said standards, and means securing said cable means with respect to said standards, said cable means consisting only of a single tightwire cable in the area between said standards positioned above the ground no more than about 48 inches.
 6. The subject matter of claim 5 in which said ground anchors have eyes and said tightening means consists of a pair of turnbuckles each having a hook engaged in an eye of one of said ground anchors and having an eye on its other end, a tension coil spring having engaging means at each end including one end engaged in the eye of one of said turnbuckles, said cable means consisting of a single cable connected to the eye of one of said turnbuckles at one enD and at the other end secured to the other end of said spring, said supporting means of each standard including a U-bolt securing said cable thereby holding the standard against tipping longitudinally of said cable.
 7. The subject matter of claim 5 in which said cable means is secured to said standards and in which each standard has ground penetrating means extending into the ground at least several inches limiting the lower end of each standard from shifting and permitting some limited but substantial pivotal adjustability of each standard as a whole of at least several degrees in the vertical plane of said cable means about the lower portion of the standard thereby accommodating tightening of said cable means, each standard having ground engaging pad means including portions spaced transversely of said cable means to each side of said cable means thereby acting to prevent sidewise tipping of the standard and bearing on said ground, said pad means extending horizontally out from the adjacent portion of each standard and having in the horizontal extension at least a couple times the horizontal area of said adjacent portion whereby said pad means has a substantial effect in limiting standard ground penetration, each standard having a platform at about the height of said cable means thereby providing supports for users in starting on said tightwire walking means and in leaving an end of said tightwire walking means, each standard having upright means extending above said cable means at least to the level of the hands of users walking on said tightwire walking means whereby users leaving said platform of a standard or coming to said platform will have an upright at hand level to grasp for support.
 8. The subject matter of claim 5 in which said cable means, anchors, and tightening means form tensed elements including only a single cable whereby the integrity of the tightwire walking means is not impaired by the securing of more than one cable.
 9. The subject matter of claim 5 in which each standard has ground penetrating means extending into the ground at least several inches limiting the lower end from shifting.
 10. The subject matter of claim 5 in which each standard has pad means bearing on said ground, said pad means extending horizontally out from the adjacent portion of each standard and having in the horizontal extension at least a couple times the horizontal area of said adjacent portion whereby said pad means has a substantial effect in limiting standard ground penetration.
 11. The subject matter of claim 5 in which each standard has a platform at about the height of said cable means thereby providing supports for users in starting on said tightwire walking means and in leaving an end of said tightwire walking means.
 12. The subject matter of claim 5 in which each standard has upright means extending above said cable means at least to the level of the hands of users walking on said tightwire walking means whereby users starting to walk the tightwire from a standard or reaching a standard from the tightwire will have an upright at hand level to grasp for support.
 13. The subject matter of claim 5 in which each standard includes an upright and pad means secured to said upright and bearing on the ground, said pad means extending horizontally out from the adjacent portion of each standard and having in the horizontal extension at least several times the horizontal area of said adjacent portion whereby said pad means has a substantial effect in limiting standard ground penetration, and said pad means having means for adjustably securing the same to said upright at various distances from said cable means thereby providing for adjustable height of the tightwire above the ground.
 14. The subject matter of claim 5 in which each standard includes a tubular upright and in which each standard includes pad means secured to said upright and bearing on the ground and limiting ground penetration by said upright, said pad means being of a size to increaSe standard ground bearing area several times, and there being interfitting tubular parts of said tubular upright between said pad means and said cable means whereby the height of the tightwire above the ground can be varied by omission or addition of interfitting tubular parts.
 15. The subject matter of claim 5 in which each standard has an upright extending from the ground to a height above said cable means at least to the level of the hands of users walking on said tightwire walking means whereby users leaving a standard to walk on the tightwire or returning to the standard from the tightwire will have an upright at hand level to grasp for support, and said upright being formed of interfitting parts permitting detachment of a portion of said upright above said cable means from the remainder of said upright thereby reducing package length in disassembly for shipment.
 16. Sports equipment in which tightwire means is supported above a supporting surface, comprising: a. a pair of spaced apart standards supported by said supporting surface b. cable means extending between said standards, said standards having means securing said cable means thereto and means supporting said standards in upright position including means engaged in said supporting surface whereby said standards are held against the tension of said cable means c. means operative to tighten said cable means between said standards d. said cable means between said standards consisting only of a single cable to form tightwire means positioned above said supporting surface no more than about 48 inches e. said cable means having secured thereto tension spring means reducing the spring rate of said cable means for the purpose of avoiding failure under normal maximum loadings.
 17. Sports equipment in which tightwire means is supported above a supporting surface, comprising: a. a pair of spaced apart standards supported by said supporting surface b. cable means extending between said standards, said standards having means securing said cable means thereto and means supporting said standards in upright position including means engaged in said supporting surface whereby said standards are held against the tension of said cable means c. means operative to tighten said cable means between said standards d. said cable means between said standards consisting only of a single cable to form tightwire means positioned above said supporting surface no more than about 48 inches e. said means supporting said standards in upright position including anchor means secured in said supporting surface at the opposite end of each standard from the other standard and said cable means extending from each standard and connecting to the associated anchor means, said cable means including only a single cable thereby avoiding impairing cable means integrity by securing more than one cable.
 18. The subject matter of claim 17 in which said means operative to tighten said cable means between said standards is a tightening member interposed between said cable means and at least one of said anchor means, and there being a secondary, by-pass safety cable secured to the cable means and extending past said tightening member and connecting to the associated anchor means whereby upon failure in the connection of the cable means to the tightening member or of the tightening member to the associated anchor means, the by-pass cable will accept the cable means load. 